[pacman-dev] [PATCH] Perform limited conflict checking with --force

[Allan McRae]

Pacman currently bails when trying to extract a file over a directory
when using --force.  Instead of ignoring all conflict, perform the
check and skip any file-file conflicts. Conflicts between directories
and files are still flagged and cause the transation to abort.

As a bonus, we now know about files changing packages when using
--force, so we can skip removing them fixing upgrade046.

Signed-off-by: Allan McRae <allan at archlinux.org>
---
 doc/pacman.8.txt                |  2 ++
 lib/libalpm/conflict.c          | 26 ++++++++++++++++++++++++--
 lib/libalpm/sync.c              |  2 +-
 src/pacman/sync.c               |  3 +++
 test/pacman/tests/upgrade046.py |  2 --
 5 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/doc/pacman.8.txt b/doc/pacman.8.txt
index 358d506..33a9421 100644
--- a/doc/pacman.8.txt
+++ b/doc/pacman.8.txt
@@ -205,6 +205,8 @@ Upgrade Options (apply to '-S' and '-U')[[UO]]
 	Bypass file conflict checks and overwrite conflicting files. If the
 	package that is about to be installed contains files that are already
 	installed, this option will cause all those files to be overwritten.
+	Using '--force' will not allow overwriting a directory with a file or
+	installing packages with conflicting files and directories.
 	This option should be used with care, ideally not at all.
 
 *\--asdeps*::
diff --git a/lib/libalpm/conflict.c b/lib/libalpm/conflict.c
index 610e5ad..6195c9c 100644
--- a/lib/libalpm/conflict.c
+++ b/lib/libalpm/conflict.c
@@ -439,8 +439,10 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 			alpm_pkg_t *p2 = j->data;
 			_alpm_filelist_resolve(handle, alpm_pkg_get_files(p2));
 
-			common_files = _alpm_filelist_intersection(alpm_pkg_get_files(p1),
-					alpm_pkg_get_files(p2));
+			alpm_filelist_t *p1_files = alpm_pkg_get_files(p1);
+			alpm_filelist_t *p2_files = alpm_pkg_get_files(p2);
+
+			common_files = _alpm_filelist_intersection(p1_files, p2_files);
 
 			if(common_files) {
 				alpm_list_t *k;
@@ -448,6 +450,18 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 				for(k = common_files; k; k = k->next) {
 					alpm_file_t *file = k->data;
 					snprintf(path, PATH_MAX, "%s%s", handle->root, file->name);
+
+					/* can skip file-file conflicts when forced */
+					if((handle->trans->flags & ALPM_TRANS_FLAG_FORCE) &&
+							alpm_filelist_contains(p1_files, file->name) &&
+							alpm_filelist_contains(p2_files, file->name)) {
+						_alpm_log(handle, ALPM_LOG_DEBUG,
+							"%s exists in both '%s' and '%s'\n", file->name,
+							p1->name, p2->name);
+						_alpm_log(handle, ALPM_LOG_DEBUG,
+							"file-file conflict being forced\n");
+						continue;
+					}
 					conflicts = add_fileconflict(handle, conflicts, path, p1, p2);
 					if(handle->pm_errno == ALPM_ERR_MEMORY) {
 						FREELIST(conflicts);
@@ -601,6 +615,14 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 				}
 			}
 
+			/* skip file-file conflicts when being forced */
+			if((handle->trans->flags & ALPM_TRANS_FLAG_FORCE) &&
+					!S_ISDIR(file->mode) && !S_ISDIR(lsbuf.st_mode)) {
+				_alpm_log(handle, ALPM_LOG_DEBUG,
+							"file-file conflict being force\n");
+				resolved_conflict = 1;
+			}
+
 			if(!resolved_conflict) {
 				conflicts = add_fileconflict(handle, conflicts, path, p1, NULL);
 				if(handle->pm_errno == ALPM_ERR_MEMORY) {
diff --git a/lib/libalpm/sync.c b/lib/libalpm/sync.c
index be55500..15e6957 100644
--- a/lib/libalpm/sync.c
+++ b/lib/libalpm/sync.c
@@ -1241,7 +1241,7 @@ int _alpm_sync_commit(alpm_handle_t *handle, alpm_list_t **data)
 	trans->state = STATE_COMMITING;
 
 	/* fileconflict check */
-	if(!(trans->flags & (ALPM_TRANS_FLAG_FORCE|ALPM_TRANS_FLAG_DBONLY))) {
+	if(!(trans->flags & ALPM_TRANS_FLAG_DBONLY)) {
 		EVENT(handle, ALPM_EVENT_FILECONFLICTS_START, NULL, NULL);
 
 		_alpm_log(handle, ALPM_LOG_DEBUG, "looking for file conflicts\n");
diff --git a/src/pacman/sync.c b/src/pacman/sync.c
index 417773d..924cdf5 100644
--- a/src/pacman/sync.c
+++ b/src/pacman/sync.c
@@ -881,6 +881,9 @@ int sync_prepare_execute(void)
 		        alpm_strerror(err));
 		switch(err) {
 			case ALPM_ERR_FILE_CONFLICTS:
+				if(config->flags & ALPM_TRANS_FLAG_FORCE) {
+					printf(_("unable to %s directory-file conflicts\n"), "--force");
+				}
 				for(i = data; i; i = alpm_list_next(i)) {
 					alpm_fileconflict_t *conflict = i->data;
 					switch(conflict->type) {
diff --git a/test/pacman/tests/upgrade046.py b/test/pacman/tests/upgrade046.py
index a02a713..d9ac66b 100644
--- a/test/pacman/tests/upgrade046.py
+++ b/test/pacman/tests/upgrade046.py
@@ -29,5 +29,3 @@
 self.addrule("FILE_MODIFIED=bin/foobar")
 self.addrule("FILE_EXIST=usr/share/file")
 self.addrule("FILE_MODIFIED=usr/share/file")
-
-self.expectfailure = True
-- 
1.8.1.3